Thermal timer for heating apparatus



April 6, 1948. E. .1. MEYERS THERMAL TIMER FOR HEATING APPARATUS Filed Nov. 19, 1945 2 Sheets-Sheet l l IAIIIIIIIIIIIHH HU II IH I l l ||l| April 6, 1948. E. J. MEYl-:Rs

THERMAL TIMER FOR HEATING APPARATUS Filed Nov. 19, 1945 2 Sheets-Sheet 2 JNVENTOR.

BY 500m/EJ /Mfyf MW Patented Apr. 6, 1948 THERMAL TIMER FOR HEATING APPARATUS Eugene J. Meyers, Los Angeles, Calif., assigner to Hayes, Meyers and Hoagland, Los Angeles, Calif., a copartnership Application November 19, 1945, Serial No. 629,360

(Cl. 21S-20) 11 claims. l

My invention relates to time controllers and has particular reference to a novel th'ermostatic time controller which nds particular utility when used to control cyclically operating apparatus, such as bread toasters, Walile bakers and the like.

In certain types of appliances, such as bread toasters, waiile bakers and the like, use is made of a simple and inexpensive time controller for controlling the duration of oper-ation of the appliance in an attempt to automatically produce a product of uniform quality. Usually these time controllers constitute bimetallic thermostatic strips which produce a motion in response to a rise in temperature. This motion is used to terminate the operation of the appliance after the passage of such a time period as may be required to heat the bimetallic element to a tripping temperature.

Prior to my invention considerable diculty has been encountered in the use of thermostatic timing elements of this character because the appliances are usually subjected to repeated operations, with the result th'at on ensuing operations the bimetallic strip is heated from an initial temperature higher than that obtaining at the beginning of the previous cycle of operations so that the time period controlled becomes progressively shorter as the device is repeatedly used. Th'is results in an undesired lack of uniformity in the product produced, requiring either a continuous adjustment of the mechanism during operation or, alternatively, requiring the automatic control to be superseded by a manual control.

It is, therefore, an object of my invention to provide a time controller which overcomes the above noted disadvantages by providing controlled time periods of uniform duration regardless of the frequency of successive operations.

It is also `an object of my invention to provide a time controller of the character set forth in the preceding paragraph' which employs a temperature responsive element for determining the duration of the controlled time period, and in which a plurality of such elements are used successively.

It is an additional object of my invention to provide a time controller of the character set forth hereinbefore which includes a means operable once each time period to transfer the time control to a long idle control element.

It is a still furth'er object of my invention to provide a time controller of the character set forth in the preceding paragraphs in which a plurality of control elements are mounted for movement successively to controlling positions and in which movement of said element results from each operation of the time controller.

It is additionally an object of my invention to provide a controller of the character set forth hereinbefore Which includes la single timing adjustment for regulating the duration of the time period controlled by each of the control elements.

Other objects and advantages of my invention will be apparent from a study of the following specications, read in connection with the acccmpanying drawings, wherein:

Fig. 1 is a perspective View illustrating as one embodiment of my invention an electric bread toaster;

Fig. 2 is a longitudinal sectional View taken substantially along the line II-II of Fig. 3 and illustrating the details of interior construction;

Fig. 3 is a cross-sectional view taken along the line lII-III of Fig. 2 and illustrating additional details of construction;

Fig. 4 is a fragmentary plan view of the time controlling mechanism and illustrating th'e relationship ofthe parts to a time period adjusting means; and

Fig. 5 is a fragmentary perspective View illustrating the construction and arrangement of a part of the mechanism.

Referring to the drawings, I have chosen an electric bread toaster for illustration in Fig. 1 as exemplary of the uses to which the time controller of my invention may be put. As is illustrated in Figs. l, 2 and 3, the bread toaster may include a suitable base member l upon which is suitably mounted upright housing and supporting members 2 and 3. These members are disposed in parallel relation to each -other and spaced apart so as to define an interior space shown at 4 into which a slice of bread, represented by the dotted outline 5, may be placed.

Upon the inner face of each of the supports 2 and 3 there are mounted sheets 6 and 'l of heatresistant electrical insulating material, such as sheet mica, upon which are mounted electrical heating elements 8. The heat produced by these elements is excluded from the spaces Within the individual housings 2 and 3 by means of h'eat insulating shields 9 and I0 positioned immediately behind each of the heating element supports E and 1.

Within the slot or space d there is mounted a bread supporting member I I which serves also as illustrated in Fig. as comprising a shallow channel-shaped member including a projecting handle or tongue portion I2 which may be grasped with the lingers for placing the device in operation. The opposite end of the member II is mounted for pivotal movement as by means of supporting brackets I3 and .I4 `secured to thegbase Landl engaged by pivot pins i5 and IB which are mounted on the end of the tray l I.

The tray I I is normally urged to a normal nonoperating position, such as is shown ir1jr' ;i g.v lpy means of a tension spring I'I connected between an upwardly extending portionwl of .thebracket I3 and an arm I9'which is secured toQl: formed integrally with the tray II and extended Yparallel thereto in a position to lie within the space enclosed within the housing 2.

Near the lngerpiece IZ there may be Vmotuited an electrical contact 2liv disposed in a position to engage another electrical contact 2I mounted upon the base member I-to thereby complete the electrical circuit through theheating elements v8 vwhen thee-tray Il-isdepressed-to an operating position', -s-uch as that shown 4in full `lines in Fig.V 2. I W- ithin the interiorvof the housing 2 there is mounted an upwardly -extendinglsupport -or post 272 to which is Asecured a horizontal-lyl extending stub ,shaft YZ123 upon which is jour-naledior rotation a control element carrier 24. Upon the Acarrier 2d there are mounted a plurality of temperature responsiye control elements 25. In thedrawings I have illust-rated four of such control elements as being spaced equally about -the circumference -of the carrier 2li. i

According to the preferred embodimentof -my invention `these control elements comprise-bimetallic strips, the outer ends of which are'turned 'laterally asY indicated at- 26 -in Fig. 3. Theelementsr2v5 are so constructedgthat When-heated, they de ect laterally; i. e., in a directionnormal i0 the plane Qf. the Strips'25.

Near the circumference offt-he -circledescr-i-bed by rotation of the control elements 2 5 Ithere -is placed a tripping member or latch 2T whichincludes a laterally extending vhook or project-ion 23 positioned at its upper end in such location as to normally be engaged bythe laterally turned DQrtionsZ' of the control ,elements 2'5 so that, as is shown in Fig. 2, counter-clockwise rotation of the element carrier 24 andthe elements-25 is lpreventedby engagement of the portion'26 with the latch 28.. Rotation in the opposite direction may be prevented by means of a pawl A29 pivotally mounted upon the Suppertand normally urged as by meansof. a springi) toa position such asis shown in Fig. 2 injwhich theYtipAS-i of the pawl 29 engages the underside o f thelaterallyturned portion 25 of the controlvelement 2.5.

The tip portion 3| yo f vthe pawl 29 -denes a Y sloping '.Surece A32v adapted to be engaged by counterclockwise rotationof the control elements and be displaced .to e pesitsmellowlne the nertiQnZe t0 be moved .into engagement withlthe latch. or hook 2.8. at yWhlell time .the Spring 31 vreturns the Daryl 29 to the .rie1t1z-1alY pesitionillustrate@ in Fia? in Wliehthe .Control elements@ held ,against .rotation :provided nthe-heatsheld l D an aperture-.33 disposed in a position to permit radiant heat energy -from the heating element 8 to fall upon the one .control element 25 which is engaged with the latch 255. Theheat shield lil effectively heet in- `sulates those of the control elements 25 which are disposed in locations away from the trip means 28.

It will be appreciated that when the one oi the elements 25 which is engaged with the latch 2S is heated to a suiiciently high temperature, the resulting lateral displacement oi the tip 2B will move that portion out of engagement with the latch 28 to thereby release the control element assembly to permit that assembly to be rotated -'in a counter-clockwise direction, at which "time Vrotation is arrested by engagement of the portion 26 of another control element with the latch 28.

*The above-described rotation of the assembly ofcontrrl elements 325 is, in the construction illustratedherein, made an incident to the movement pi the controller/er ,or bread tray I I from the operating position shown in full lines in Fig. 2 to 'the -normal or non-operating position shown by dotted lines in that figure., This is accomplished yby Vpivota'lly mounting upon the end .of the arm 19a link'SLI .whichis pivotal'ly attached .to a crank 35 journaled for rotation upon the stubshaft 2.3. vllhe crank .3.5 supports a pawl 36, .the nose 3l' of which rides the periphery .of a four notch ratchet 3B.

The ratchet 38 is secured to `the control elelment carrier 2d and is sopositioned that When the control lever II is moved to an operating Aposition vsuch as is shown in solid lines in Fig. 2, the nose -3l of the pawl :36.will engage `one of the notches of the rat-Chet v3d. The spring I'lwhch normally urges the control lever I I toward its normal Vposition thus applies through the arm I9, line 136, crank 35 and pawl 36 a torque to the assembly .of control elements tending to rotate those elements in a counter-clockwise direction. Accordingly when the one control element which is positioned under the latch 23 is heated s ufciently to disengage the portion 26 from the latch 2,8, the vspring Il will lift the control Il to its normal `position and at the same time rotate the assembly of control elements through an angle of 9.0" to position another control element in engagement with the latch 28. This upward movement of the vcontrol lever or bread tray Il will lift the slice of bread .5 to a position such as is represented by the dotted outline in Fig. 1, -permitting Yready removal of a slice of toast from the device.

`When the Idev-ice is placed in operation a second time by moving the control lever Il from its normal position to its operating position, the pawl -2-9 holds the control element assembly against rotation so that the pawl 36 is moved over the peripheral surface of the ratchet 3S to .a positionengaging the nose 3l of the pawl with anothernotch of the ratchet. At the endrof the time required to.heat the control element sutil- .ciently to disengage the portion 25 thereof from the latch 28, the control lever II Willreturn to its; initial position and the assembly of control elements25 will be rotated through another 90.

It will be noted that by this construction three of the four control elements are shielded from the heat generated by the heating element il and that each element is employed to regulate the duration of the time of operation `of the device only once out of each four operations sothat each of the timeperiods of operation is controlled by a control element which has been allowed suicient time to cool to; a substantially uniform initial temperature. By this means I have assured that the time periods which are determined by the heating of the control elements will all be of uniform duration.

I have included also in the device of my invention a means for adjusting the length of the controlled time periods. This means preferably comprises a cam wheel 39 which is mounted for rotation as by means of a shaft 40 carried in supporting brackets 4I secured to the inner surface of the outer wall of the housing 2. The cam 39 presents a spiral or eccentric surface 42 which engages the side of the post 2l so that by pivotally moving the cam 39, thel post 2l may be flexed to move the latch portion 28 thereof in the same direction as the tip 26 o-f the control element 25 is moved by a change in temperature of the control element. Therefore, rotation of the adjustment means 39 regulates the distance through which the tip 26 of the control elements 25 must move in order to disengage the control element assembly from the latch 28. Thus the adjustment means 39 operates to adjust the duration of the time period controlled by the controller, and it is pointed out that this one adjustment means serves to adjust the operating time of all of the plurality of controlling elements 25.

While I have described the device of my invention as forming an integral part of a controlled device which has been illustrated herein as comprising a bread toaster, it will be appreciated that the device may be used for the control of any 'electrical apparatus merely by connecting that apparatus in parallel with the heating elements 8.

It will also be appreciated that the mechanism is suitable for use on other types of appliances, such as waflie bakers, electric stoves and similar devices.

Attention is directed particularly to the fact that I obtain a uniform measured time interval by providing a plurality of time controlling elements which are operated in succession so that each element is allowed a sunicient time to cool to a uniform initial temperature before that element is again used to control the operation of the device.

While I have shown and described the preferred embodiment of my invention, I do not desire to be limited to any of the details of construction shown or described herein, except as defined in the appended claims.

I claim:

l. A time controlled device comprising: the combination of: means for initiating an operation; a plurality of temperature responsive control elements; means for exposing said elements successively to an operating location; a heater for applying heat to said location; means controlled by the one element at said location for terminating said operation upon a rise in temperature of said one element to a predetermined value; and a connection with said controlled device for automatically moving said elements upon operation of the device, whereby unused control elements will be permitted to cool before again being subjected to heat.

2. In a time controlled device employing thermally responsive elements capable of reproducing calibrated time periods, the combination of: means for initiating an operation; a plurality of temperature responsive control elements; a mounting for said elements for effecting movement successively to an operating location; a heater for applying heat to said location; a cutoff controlled by one element at said location for terminating said operation upon a rise in temperature of said one element to a predetermined value; and a mechanism responsive to termination of said operation for moving said elements.

3. In a time controlled device employing thermally responsive elements capable of reproducing calibrated time periods, the combination of: means for initiating an operation; means for applying heat to an operating location; a plurality of temperature responsive control elements; means controllable by a control element at said operating location for terminating said operation upon a rise in temperature of said element to a predetermined value; means mounting said elements for movement successively to said operating location; and means operable alternately with said controlled device for moving said elements to shift said one element away from said operating location and move another element to said location.

Ll. In a time controlled device employing thermally responsive elements capable of reproducing calibrated time periods, the combination of z means for initiating an operation; a heater for applying heat to an operating location; a plurality of temperature responsive control elements; means controllable by a control element at said operating location for terminating said operation upon a rise in temperature of said element to a predetermined value; means mounting said elements for movement successively to said operating location; and a mechanism responsive to termination of said operation for moving said elements to shift said one element away from said operating location and move another element to said location.

5. In a time controlled device including a heat producing member, the combination of: means for initiating operation of said device; trip means for terminating said operation; a plurality of temperature responsive control elements each including a portion movable from a normal position in response to a rise in temperature of said elements; means mounting said elements for movement successively `to a position normally engaging said portion with said tripping means; means for directing heat from said member upon the one element engaging said trip means and for heat shielding all other control elements; and means operable alternately with said member for moving said elements to shift said one element away from said trip means and move another element into engagement therewith.

6. In a time controlled device including a heat producing member, the combination of: means for initiating operation of said device; trip means for terminating said operation; a plurality of bimetallic control elements each including a por tion movable from a normal position in response to a rise in temperature of said elements; means mounting said elements for movement successively to a position normally engaging said portiQIl :movable from a normalposition in response .to a risen; .temperatureof said elements; means :mounting s aid',.elements for movement successively tol a position normally engaging said por- 121911-Wth-Saidtripmeans; heat shield means disposed between said heat producing member and all ofsaid control elements, said shield having an aperture .therein ina position to direct heat 1frornsaid member 119.011 the one element engagingsaid trip .means;.an'd means operable alter- ;nately .with .said member for moving said elevments to .shiitsaid .one element away from said .trip .means and V.move another element into eneasement therewith.

Q8. I- n ,a time controlleddevice including a heat .producing member, the .combination of: means for initiatingoperation of said device; trip means for yt.erminating s aid operation; a plurality of cbirgnetallic control elementseach including a portion movable from a normal position in response to arise in .temperature 0f said element; a rotatable element carrier;V means mounting said ele- .ments .in uniform angular spaced relation from veach other zupon saidcarrier vfor movement successively `.to .a position normally engaging said portionlwith said trip means; .heat shield means .disposed .between said :heat producing member and allofsaid control elements, said heat shield vmeans having .van aperture therein disposed in a position to .direct heat from said member upon the one element engaging 4said trip means; and means operablealternately with said member for rotating .said element carrier to shift said one element vaway from vsaid trip means and move another element into engagement therewith.

9. In a time controlled device including a heat producing member, vthe combination of: starting means movable from a normal position to an operating position for initiating operation of said device; trip means for terminating said operation; a plurality Tof bimetallio control elements each including a portion movable from a normal position in response to a rise in temperature of said element; a rotatable element carrier; means mounting said ,elements in .uniform angular spaced relation from each other upon said carrier for movement successively to a position normallyengaging said portion with said trip means; -heat .shield -means 'disposed between said heat producing member and all of said control elements, said heat shield Vmeans having an aperture therein disposed in a position to direct heat from said member upon ythe one element engaging said trip means; and lmeans responsive to movemen-t in one direction of said starting means for rotating said element carrier to shift said one operation; `a plurality of cbimetallic control elements-.each includinga portion movable .from a normal .position in response to arise in temperature v of saidelement; ,arotatable element carrier; meansmounting saidelements in uniform angular spaced relation from each other upon said carrier for movementsuccessively to a position normally Aengaeine said vportion with said trip means; heat shield Ameans vcliSposed 'between said heat ,producing vmellfiloer and allof said control elements,v said -heat .shield meanshaving an aperture therein disposed in aposition to Vdirect heat iromsaid member uponthe one element engaging Said trip means.; and pawl and ratchet means interconnecting .said `.staltins means with Sad element `carrier .for rotating Said carrier in respense tomovementinone direction of said startine `means to'thereby shift Said one element out of .engagement with said trip `means ,andmove .another element into Aengagement therewith.

.1 1. ,I n a vtime controlled device including a heat producing .memben the combination of: means .for initiating `operation of Ysaid :device: `trip .means vfor terminating said operation; a. plurality of 'bimetallic Vcontrol elements cach Vincluding a portion movable from a normal .position in response vto a rise .in temperature Yof `said elements; means mounting said ele-ments for movement successively .to a position normally engaging said portion with said trip means; adjustment means Vfor varying the extent of the ynormal engagement of -saidloortion With said trip means; means for Adirecting 'heat from .said member upon the one .element engaging said trip means and for 'heat shielding all `other control elements; and means operable alternately with said member for moving said elements to shift said one element away from said trip means and mcfle another element into .engagement therew1,

EUGENE J. MEYERS.

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